Keyboard and trackpad still unresponsive after replacing cable

Thank you for your answer! I attempted a hard SMC reset, the method you described didn’t do anything so I followed step 3 on this guide: How to Reset the SMC on MacBooks)

It seemed like it worked. The computer didn’t turn on when I pressed and held the key combo of shift+control+option on the left side of the keyboard + the power button. I reconnected the power adapter and pressed the power button and the computer turned on but booted into internet recovery mode. I restarted a few times until it booted normally but the keyboard + trackpad were still unresponsive.

In the USB section of the system report it does not list the keyboard or trackpad.

It seemed like the computer recognized the keys I pressed to do the hard reset of the SMC but otherwise they are still not working.

I don’t know if this is relevant but the computer is running on a 3rd party ssd. It worked fine for years but internet recovery mode doesn’t recognize it as a valid boot drive.

@progrockgf - As you don’t see the keyboard/trackpad in the USB listing that implies either the trackpad cable is bad/damaged or the cable is not properly connected to the connectors. With the more remote possibility of a logic board problem.

As long as the macOS is able to load there is nothing related to the drive here directly. If you are using a M.2 drive then the adapter could be causing errors reading/writing to the drive. I recommend using an external bootable drive to remove that question.